How Do the Face-Building Cells Get to the Right Place?
Take the reading one piece at a time. For each piece: read it once, underline the sentence that says what happens, then look up any word in the list. Tap a word to see its definition.
Piece 1 of 2
After they break free, cranial neural crest cells travel in three organized migratory streams. Picture the embryo from the side with the brain at the front-top: the forebrain and midbrain crest fills the frontonasal process (the midline above the mouth), the first-arch stream fills the first pharyngeal arch (which becomes the maxillary and mandibular processes), and later streams fill the second and further arches. The cells that build Mateo's upper lip ride the front streams into the frontonasal process and the first arch, exactly the prominences that must fuse to make the lip.
Piece 2 of 2
When neural crest cells cannot migrate properly, the prominences they were supposed to fill end up too small, described as hypoplastic. Compare two embryos. In Embryo A (normal), cells delaminate, migrate in streams, and arrive in full numbers and on time, so the frontonasal and maxillary blocks fill out and can meet. In Embryo B (migration disrupted), the cells are made but fewer reach the front of the face, or they arrive late, so the blocks are smaller and may not reach across to fuse.
Reading the Research
- Skim the title and abstract first to get the gist.
- Circle the one sentence that states the main claim.
- Box the evidence the authors give for that claim.
- Mark one sentence that confuses you, and move on.
Now put it together: In one or two sentences, say what this whole reading is telling you about Mateo. Then go back to the lesson and fill in the guided notes.